Express your answer as a mixed number simplified to lowest terms. $6\dfrac{8}{15}-1\dfrac{7}{9} = {?}$
Answer: Find a common denominator for the fractions: $= {6\dfrac{24}{45}}-{1\dfrac{35}{45}}$ Convert ${6\dfrac{24}{45}}$ to ${5 + \dfrac{45}{45} + \dfrac{24}{45}}$ So the problem becomes: ${5\dfrac{69}{45}}-{1\dfrac{35}{45}}$ Separate the whole numbers from the fractional parts: $= {5} + {\dfrac{69}{45}} - {1} - {\dfrac{35}{45}}$ Bring the whole numbers together and the fractions together: $= {5} - {1} + {\dfrac{69}{45}} - {\dfrac{35}{45}}$ Subtract the whole numbers: $=4 + {\dfrac{69}{45}} - {\dfrac{35}{45}}$ Subtract the fractions: $= 4+\dfrac{34}{45}$ Combine the whole and fractional parts into a mixed number: $= 4\dfrac{34}{45}$